The present invention relates to a glass-fiber filter material for use in high temperature environments, to a composition which imparts heat resistance to the filter material and to a process for making the composition.
High temperatures filters are used extensively in the automotive industry to filter heated air from paint drying ovens on automobile assembly lines. These filters permit the recycling of high temperature air for use in the paint drying process, without compromising the exterior finish of the automobiles.
The high temperature, glass-fiber filter materials currently being supplied to the automotive industry are generally rated at 450.degree. F. for continuous operation. If used at high temperatures, the glass fibers tend to become embrittled and fragile, thus risking possible breakthrough of unfiltered air, with obvious adverse consequences on the automobile painting operation. Moreover, the manufacture of these prior art high temperature filter materials often involves the use of costly, and sometimes potentially hazardous substances, as well as complex production procedures.
Accordingly, a need exists for a high temperature filter material which possesses satisfactory strength and filtration efficiency at temperatures in excess of 450.degree. F., and which may be produced at reasonable cost.